1. Field of the Invention
This invention relates to a solid delivery system (SDS) for active agricultural chemicals, and, more particularly, to a bioenhanced, stable SDS for sulfonyl and sulfamoylurea agricultural chemicals capable of forming aqueous microdispersions or tank mixes thereof suitable for application to a plant site.
2. Description of the Prior Art
Sulfonyl and sulfamoylurea (SU) herbicides are very susceptible to hydrolysis in water or in admixture with other polar organic solvents which promote proton exchange between such chemicals and the solvent. Particularly, both the sulfonyl and sulfamoylurea compounds have a labile sulfonamide bridge which decomposes readily in water. Accordingly, stabilized liquid emulsifiable concentrates of such herbicides have been developed which when added to water to form a tank mix are suitable for application to a plant site. Such liquid emulsifiable concentrates are described by Narayanan et al. in copending U.S. patent application Ser. No. 08/733,285, filed Oct. 17, 1996.
Narayanan, in U.S. Pat. No. 5,389,297, also has described an inert matrix composition in the form of a free-flowing, high melting solid suitable for making a microemulsifiable concentrate by slurrying the active with a small amount of water, and freeze-drying. This concentrate will provide an aqueous microemulsion upon dilution with tank mix water. However, for sulfonyl and sulfamoyl ureas, as described in this invention, it is more advantageous to keep these actives and water apart until the final application step, so as to minimize the hydrolysis effect on such actives, while maximizing the bioenhancing capability of the N-octyl pyrrolidone component of the inert matrix composition on these actives.